Micromechanical devices are small structures typically fabricated on a semiconductor wafer using techniques such as optical lithography, doping, metal sputtering, oxide deposition, and plasma etching similar to those developed for the fabrication of integrated circuits.
Digital micromirror devices (DMDs), sometimes referred to as deformable micromirror devices, are a type of micromechanical device. Other types of micromechanical devices include accelerometers, pressure and flow sensors, gears and motors. While some micromechanical devices, such as pressure sensors, flow sensors, and DMDs have found commercial success, other types have not yet become commercially viable.
One problem common to most micromechanical devices is the problem of particulate contamination. While some micromechanical devices, such as pressure sensors, may not have exposed moving parts, most devices do have exposed components that move relative to each other. These moving parts can become mechanically blocked or electrically shorted by very small particles of debris. Although steps are taken during manufacture of the devices to clean debris from the devices, the fragile nature of some micromechanical devices and other factors conspire to prevent total elimination of the debris. Thus, debris inside micromechanical packages continues to be a significant cause of mechanical and electrical failures. What is needed is a way to prevent these failures caused by debris inside the micromechanical device package.